In communication systems operating at less than 10 Ghz, silicon bipolar transistors can be used. The making of devices for microwave applications has been expensive such as for the making of bipolar MMIC devices using conventional bulk silicon technology. This problem occurs because of the process complexity associated with buried collectors and isolation of the parts.
The making of such devices with SOI technology reduces the complexity of the process with the added advantage of low capacitances. But while a lateral bipolar transistor can be made for use at microwave frequencies, high power has not been achieved in such devices.